The present invention relates to a foldable, portable optical instrument, and more particularly to an optical apparatus for providing video signals corresponding to an original image, the video signals being input to a video monitor or a video deck to display the image.
There are various types of foldable and portable optical instruments, such as an image input apparatus for transmitting video signals of an original image provided by a video camera to a CRT monitor or a video deck or overhead projectors for projecting an image onto a remote screen. Some such image input apparatuses are portable and are covered to protect their optical systems and video cameras when not in use.
An image input apparatus of the just-mentioned type is provided with a cover pivotably mounted on a box-like body casing, enabling pivotal movement for opening and closing the body case. The casing of the image input apparatus has a table for placing an original thereon. The cover incorporates a lighting system for illuminating the original placed on the table and a reflective mirror for reflecting and directing an image of the original to a video camera disposed in the body casing.
Such foldable, portable optical instruments have poles, fixedly mounted on body casings for holding lighting systems to illuminate an original and a video camera to take an image of the illuminated original. To provide a sharp and clear image, various types of lighting systems are prepared to cooperate with such instruments or are incorporated therein to provide even illumination over the document.
In order to avoid flaring or ghosting of the image, the optical instruments usually are provided with shading members to prevent an original placed on the table from receiving ambient light or light from room lamps. With the recent improvement of image sensor elements, the image input apparatus has become lighter and more compact. To facilitate portability, such lighting systems and/or shading members are adapted to be disassembled and stored in a carrying case of the optical instrument.
Also, the foldable, portable optical instruments are provided with carrying handles which can be brought down when they are not in use, for ease of carrying.
Generally, it is difficult to make the above noted optical instruments more compact, and especially thinner, and to illuminate an original uniformly. Further, these instruments are structually and mechanically weak because the carrying handles are mounted on brackets which, though required to support a heavy instrument, usually are small and weak because of the need for compactness of the instruments. Therefore, the carrying handle and its associated parts are broken easily.
In addition to the above noted drawback, the optical instruments with foldable lighting systems are somewhat difficult to fold and unfold. Further, the shading member for use with the foldable, compact optical instruments is relatively small in size and, therefore, is not effective to shut off undesired illumination, so that flaring or ghosting often is created.